Epson 9600 Service Manual - Page 108

EPSON Stylus Pro 7600/9600 † P_EDGE (Paper Width Detection) Sensor This sensor, mounted at the left side of the cutter unit of the carriage, detects paper edges by moving the carriage. It detects four points of paper edges, namely, left and right points on the front edge and a front point on the left and right edges of the paper. Each position is calculated from the difference in reflection value between the platen and the paper. A reflective type photosensor is used. Each paper edge position (presence or absence of paper) is determined by an A/D converted value of the output from the photosensor. During printing, the sensor monitors the left and right edges of the paper to detect a skew. „ Detecting distance up to the paper surface: 7.0mm ± 0.5 CHECK P O IN T „ It must be ensured that the reflection value of the least reflective paper is greater than the reflection value of the platen. „ The paper must be free from floating at the detection point. „ If external light, such as sunlight, can enter the sensor due to the construction, mis-detection must be prevented by LED ON/ OFF control. (Same as with Stylus Pro 7000) „ In Stylus Pro 7600/9600, the P_EDGE Sensor works also to detect the paper front edge. (Stylus Pro 7600/9600 does not have the P_FRONT Sensor for exclusive use to detect the paper front edge which is incorporated in the conventional printer models.) NOTE: It is possible to turn this sensor off by "SelecType" (p.35). The following pages show paper size detection sequence (left and right edges and front edge). Left edge Right edge Revision A Carriage Scanning of HP side → Opposite side Scanning of opposite side → HP side HP Side P_EDGE Sensor Figure 2-6. Carriage Unit Paper Width Detection Sensor Operating Principles Print Mechanism Components 108